The long-range goal of the proposed research is to solve the problem of pollen-caused hay fever and asthma by eliminating or reducing the seasonal production of air-borne allergenic pollen, particularly ragweed pollen. A direct attack on the problem will be made and will include: (1) devising treatments (chemical sprays and other) which should interfere with ragweed growth, flowering or pollen shed; (2) obtaining, if possible, genetically variant ragweeds which produce non-allergenic pollen and attempting to spread this trait in a population of normally allergenic ragweeds. Other research will be conducted to gain an improved understanding of ragweed reproductive physiology to provide a fund of knowledge on ways to reduce allergenic pollen production, if the direct attack on the problem is not successful. The latter studies include determination of the sites of formation of ragweed antigen E, the nature of the thickened pollen wall in which the antigen is deposited during pollen maturation, and the manner in which antigen deposition in the wall occurs. Methods include radio-labeling of ragweeds with cell wall precursors and identification of labeled products, quantitative determination of ragweed antigen E by radioimmuno-assay, and cytological localization of the ragweed antigen by a fluorescent antibody procedure.